Current and future public health is characterized by the increase of chronic and degenerative diseases, corresponding to the worldwide ageing of the population. The increasing prevalence of these conditions together with the long incubation period of the chronic diseases and the continual technological innovations, offer new opportunities to develop strategies for early diagnosis.
Public Health has an important mandate to critically assess the promises and the pitfalls of disease screening strategies. This MOOC will help you understand important concepts for screening programs that will be explored through a series of examples that are the most relevant to public health today. We will conclude with expert interviews that explore future topics that will be important for screening.
By the end of this MOOC, students should have the competency needed to be involved in the scientific field of screening, and understand the public health perspective in screening programs.
This MOOC has been designed by the University of Geneva and the University of Lausanne.
This MOOC has been prepared under the auspices of the Ecole romande de santé publique (www.ersp.ch) by Prof. Fred Paccaud, MD, MSc, Head of the Institute of Social and Preventive Medicine in Lausanne (www.iumsp.ch), in collaboration with Professor Antoine Flahault, MD, PhD, head of the Institute of Global Health, Geneva (https://www.unige.ch/medecine/isg/en/) and Prof. Gillian Bartlett-Esquilant (McGill University, Quebec/ Institute of Social and Preventive Medicine, Lausanne).

From the lesson

Evaluation, Planning, Implementation and the Future of Screening Programs

In this final module, important aspects of for the evaluation, planning and decision making about the implementation or stopping of screening programs will be presented. This material is given by Senior lecturer Jean-Luc Bulliard who is an epidemiologist in the Division of Chronic Diseases at the Institute for Social and Preventive Medicine in Lausanne. The conclusion of the module will be a series of interviews with experts on the future of disease screening in public health conducted by Dr. Gillian Bartlett-Esquilant, a visiting professor at the Institute for Social and Preventive Medicine at Lausanne. A quiz will close this module.

Meet the Instructors

Antoine Flahault

Professor of Public Health and Director of the Institute of Global Health (Faculty of Medicine, University of Geneva) and co-Director of Centre Virchow-Villermé (Université Paris Descartes)University of Geneva and Université Paris Descartes – Sorbonne Paris Cité

Fred Paccaud (In Partnership with UNIGE)

Professor of epidemiology and public health and Director of the Institute of social and preventive medicineLausanne University Hospital

Gillian Bartlett-Esquilant

Professor of Epidemiology and Research and Graduate Program Director and Associate Chair for the Department of Family Medicine at McGill University.University of Lausannne and McGill University

[MUSIC]

In this presentation, I will give you a brief overview of the main types of

controversies we can encounter in the general framework of screening.

A different type of controversy with very different natures.

The four main ones are, first, the concept of screening itself,

which is challenged by people. It’s a followed precept in healthcare throughout

the world, that we should not risk causing more harm than good.

« first do not harm ».

And this precept is to some extent challenged by screening.

The second cause of controversy is

scientific dissent, very different estimates of benefit and

harms measured by different scientists in the world.

How could there be such differences sometimes based on the same data or

the same health care context?

The third area is communications.

What communication should be provided?

Is it intended to encourage attendance, or to allure people to make informed choice?

And then what information, how, and by who should it be conveyed?

And fourth area of controversies are the potential

conflict of interest, not only financial,

maybe political or intellectual.

So let's look at the first concept of screening itself.

Screening fundamentally differs from the clinical practice.

In practice, you treat sick people.

They could be harmed from your treatment, but

But at least they’ll have a chance of benefiting from it.

This is quite different from screening because some of the people who had

suffered the side effect from screening do not have the disease, which is

intended to be screened, so they would not be able to benefit from the interventions.

So there should be a general acceptance that screening isn't

always the right thing.

It harms as well as benefits, and

then the benefits should outweigh the harms and all that at an affordable cost.

So in terms of controversy, it can be summarized by some simple questions.

Is it, for instance, acceptable to cause death of a healthy person in

order to benefit many others?

Is it also acceptable to spend limited healthcare resources for

an intervention targeting only a subgroup of the population?

These are the kind of recurrent questions and

controversies about screening in general.

The second area of controversy, the scientific dissent,

it has to be recognized that screening evaluations is an area of expertise

as is nursing, public health, It is an area of itself, and

unraveling the methodological aspect, statistical methods

Metrics of screening is not an easy task to perform, to understand, and to explain.

So explaining then from the same data different scientists have arrived

At different reasons. Based generally on different methods,

is quite challenging to explain to the lay public,

general populations, or the journalists.

It is challenging because, first, you need to have some statistical knowledge

to explain, to understand that, and also, because the topic is not something

which is perceived as very interesting by the journalist or the public.

It is much easier for a journalist to conclude the different result for

the different people argue to a quarrel of experts.

But often it is not the case,

it is due to submission issue which are not easy to explain.

And it does create confusions about benefit and harms of screaming and

can give these wrong impressions of a quarrel among experts.

What contributes to that also is the lack of clear metrics

about how to balance the benefits and harms of screaming.

For instance, I've looked at breast cancer screening

because it has been in 2013 in the panel review with the UK.

One of the conclusions was for any life saved by screening,

there was three cases of a woman being over diagnose.

So we see case of a diagnosis for one death avoided.

Is it a very good, is it a moderate

Is it a sufficient balance of benefit and harm?

There are no really clear metrics to answer these questions.

This issue goes beyond scientific evidence and our values, and

how much are authorities are willing to pay to save a life.

Even when scientists agree on the magnitude of

the benefits and harm for screening, they can be disagreement on

how to communicate scientific reasons to the population.

We know that how to frame the information and

framing is a jargon, saying how to present the information to the public or

to the medical professionals can affect the judgement and the behaviors.

Let's take an example.

Without a screening intervention, we may have 4 deaths 1,000 operations.

And 4 in 1,000 with a screening intervention.

So you can't frame it as saying there is 20% reduction in deaths due to screening.

5 in 1,000 versus 4 in 1,000 is 20%.

But you may look at the absolute reductions which is 1 5

minus 4 in 1000 which sounds far less impressive and

people did tend to be impress by larger numbers.

But actually talking about why they're saving 1,000 is much easier

in terms of numbers to understand and to grasp the populations and the relative scales.

You can play with these numbers and say, for instance,

what is my chance of not dying from the disease?

So you'll be asking yourself before deciding whether or

not you may want to be screened.

And in this present situation, without screening,

you may have 995 chance out of 1,000 not dying of a disease.

And we spending 996 out of 1,000.

So you risk all qualified person or 1 chance in 1,000

less of dying from screening, from the disease if you get screened.

In other words you need to screen 1,000 people to save one life,

Which is a way that maybe public health

authorities are interested in seeing that. You can see for the same figures, the way it is presented, that it